Method of intravascularly delivering stimulation leads into direct contact with tissue

ABSTRACT

A method of treating a disorder in a patient is provided. The method comprises delivering a stimulation lead within a blood vessel, intralumenally puncturing a wall of the blood vessel to create an exit point, and then introducing the stimulation lead through the exit point into direct contact with tissue the stimulation of which treats the disorder. Optionally, the method comprises implanting a source of stimulation within the patient&#39;s body, and then electrically coupling the proximal end of the stimulation lead to the implanted stimulation source. Using the stimulation lead, the tissue can then be stimulated in order to treat the disorder.

RELATED APPLICATIONS

This application is related to copending U.S. patent application Ser.No. 10/xxx,xxx (attorney docket number 2024730-7037002001), filed on thesame date, and expressly incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to the treatment of diseases, and in particular,the therapeutic treatment of tissue using electrical stimulation.

BACKGROUND OF THE INVENTION

It is known to treat neurodegenerative diseases, such as Alzheimer'sDisease, Parkinson's Disease, Tremor, and Epilepsy, and ischemia of thebrain, such as stroke, by electrically stimulating selected portions ofthe brain. Currently, this is accomplished by first drilling a burr holethrough the patient's cranium in order to gain access to the braintissue. A stimulation lead, and in particular, a lead with multipleelectrodes extending along its length, is then introduced through one ormore burr holes into contact with the selected brain tissue. In a deepbrain stimulation (DBS) procedure, typically used to treat Parkinson'sDisease, Tremor, and Epilepsy, the stimulation lead is advanced througha burr hole deep into the brain, e.g., the anterior thalamus,ventrolateral thalamus (Thal), internal segment of globus pallidus(GPi), substantia nigra pars reticulata (SNr), subthalamic nucleus(STN), external segment of globus pallidus (GPe), and neostriatum. In acortical brain stimulation procedure, typically used to rehabilitatestroke victims, the lead is introduced through two burr holes and placedunderneath the dura matter in contact with the cortex of the brain.

Once the lead is properly located in contact with the selected braintissue, the proximal end of the lead or an extension lead issubcutaneously routed from the burr hole underneath the patient's scalp,down the neck, and into the chest region in electrical connection withan implanted electrical stimulator. The electrical stimulator isprogrammed either prior to or after the procedure to deliver electricalpulses to the brain tissue via the stimulation lead.

Although the current brain stimulation techniques used to treatneurological disorders have proven to be successful, such techniques arestill quite invasive, requiring the cranium to be opened through atleast one burr hole. In addition, the need for a burr hole furthercomplicates the procedure—not only requiring the additional step ofaccessing the patient's cranium while attempting to minimize tissuetrauma, but also requiring that the burr hole be capped at the end ofthe procedure. Also, additional risks are posed by the possibility thatthe burr hole may become infected and the routing of the stimulation orextension leads through the neck in close proximity to the jugular veinsand carotid arteries.

Thus, there remains a need to provide improved methods, apparatus, kits,and systems for therapeutically stimulating tissue.

SUMMARY OF THE INVENTION

In accordance with the present invention, a method of treating adisorder in a patient is provided. The disorder can be any afflictionsuffered by the patient, such as a degenerative disease or infarction.Because of the minimally invasive nature of the method, the presentinvention particularly lends itself well to the treatment ofneurological disorders, but can be applied to other disorders as well.

The method comprises delivering a stimulation lead within a bloodvessel. The lead can take the form of any lead, such as an electricalstimulation lead, that is capable of therapeutically stimulating tissue.In one embodiment, the stimulation comprises an exposed signal wire andan electrode coupled to the exposed wire. In another embodiment, thestimulation lead comprises a catheter having a catheter body, a signalwire extending through the catheter body, and an electrode mounted tothe catheter body in electrical contact with the signal wire.

The method further comprises intralumenally puncturing a wall of theblood vessel to create an exit point, and then introducing thestimulation lead through the exit point into direct contact with tissuethe stimulation of which treats the disorder. In one preferred method,the vessel wall can be intralumenally punctured by introducing a guideelement (e.g., a stylet) through the vessel wall, in which case, thestimulation lead can be conveniently introduced along the guide element(e.g., over the guide element or through a lumen within the guideelement) and through the exit port. In this case, a catheter can beintroduced into the vessel, the distal end of the catheter deflectedtowards the vessel wall at an obtuse or perpendicular angle, and theguide element introduced from the deflected distal end of the catheterand through the vessel wall. The catheter may comprise the stimulationlead, in which case, the catheter can then be introduced over the guideelement through the exit point in the vessel wall.

To prevent or minimize blood loss, the blood flow upstream from the exitpoint can be totally or partially occluded and/or the exit point can besealed after the stimulation lead has been introduced through the exitpoint. Optionally, the method comprises implanting a source ofstimulation within the patient's body, and then electrically couplingthe proximal end of the stimulation lead to the implanted stimulationsource. Using the stimulation lead, the tissue can then be stimulated inorder to treat the disorder.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of preferredembodiment(s) of the invention, in which similar elements are referredto by common reference numerals. In order to better appreciate theadvantages and objects of the invention, reference should be made to theaccompanying drawings that illustrate the preferred embodiment(s). Thedrawings, however, depict the embodiment(s) of the invention, and shouldnot be taken as limiting its scope. With this caveat, the embodiment(s)of the invention will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 is a plan view of an intravascular brain stimulation systemconstructed in accordance with a preferred embodiment of the presentinvention;

FIG. 2 is a perspective view of an alternative embodiment of astimulation lead that can be used in the system of FIG. 1;

FIG. 3 is a schematic diagram of the system of FIG. 1 in a monopolararrangement;

FIG. 4 is a schematic diagram of the system of FIG. 1 in a bipolararrangement;

FIG. 5 is a schematic diagram of the system of FIG. 1 in another bipolararrangement;

FIG. 6 is a plan view of an intravascular brain stimulation kit arrangedin accordance with a preferred embodiment of the present invention;

FIG. 7 is a close-up view of a stimulation lead with an electrolyticallydetachable pusher element used in the kit of FIG. 6;

FIG. 8 is a cross-sectional view of one preferred embodiment of adelivery catheter used in the kit of FIG. 6, taken along the line 8-8;

FIG. 9 is a cross-sectional view of another preferred embodiment of adelivery catheter used in the kit of FIG. 6, taken along the line 9-9;

FIG. 10 is a cross-sectional view of still another preferred embodimentof a delivery catheter used in the kit of FIG. 6, taken along the line10-10;

FIG. 11 is a cross-sectional view of yet another preferred embodiment ofa delivery catheter used in the kit of FIG. 6, taken along the line11-11;

FIG. 12 is a cross-sectional view of the delivery catheter of FIG. 11,wherein an electrode is particularly shown passing through one of thestimulation lead delivery lumens;

FIGS. 13A-13G are side views illustrating a method of intravascularlydelivering stimulation leads into various superior cerebral veins withinthe brain of a patient using the kit of FIG. 6, wherein the deliverycatheter of FIG. 8 is used;

FIGS. 14A-14F are side views illustrating another method ofintravascularly delivering stimulation leads into various superiorcerebral veins within the brain of a patient using the kit of FIG. 6,wherein the delivery catheter of FIG. 9 is used;

FIG. 15 is a side view of the monopolar arrangement of the system ofFIG. 1 arranged in accordance with the schematic diagram of FIG. 3 tostimulate the cortical tissue of a patient's brain;

FIG. 16 is a side view of the bipolar arrangement of the system of FIG.I arranged in accordance with the schematic diagram of FIG. 4 tostimulate the cortical tissue of a patient's brain;

FIG. 17 is a side view of the bipolar arrangement of the system of FIG.1 arranged in accordance with the schematic diagram of FIG. 5 tostimulate the cortical tissue of a patient's brain;

FIG. 18 is a partially cutaway side view of an alternative embodiment ofa delivery catheter that can be used in the kit of FIG. 6;

FIG. 19 is a cross-sectional view of the delivery catheter of FIG. 18,taken along the line 19-19;

FIG. 20 is a partially cutaway side view of another alternativeembodiment of a delivery catheter that can be used in the kit of FIG. 6;

FIG. 21 is a cross-sectional view of the delivery catheter of FIG. 20,taken along the line 21-21;

FIG. 22 is a perspective view of another intravascular brain stimulationkit arranged in accordance with a preferred embodiment of the presentinvention;

FIGS. 23A-23F are side views illustrating a method of intravascularlydelivering stimulation leads into the brain of a patient using the kitof FIG. 22;

FIG. 24 is a plan view of another stimulation lead constructed inaccordance with a preferred embodiment of the present invention;

FIG. 25 is a cross-sectional view of the stimulation lead of FIG. 24,taken along the line 25-25;

FIG. 26 is a side view of the stimulation lead of FIG. 24 shownstimulating brain tissue of a patient from a superior cerebral vein;

FIG. 27 is a side view of the stimulation lead of FIG. 24 shownstimulating brain tissue of a patient from the superior sagittal sinus;

FIG. 28 is a plan view of still another stimulation lead constructed inaccordance with a preferred embodiment of the present invention;

FIG. 29 is a cross-sectional view of the stimulation lead of FIG. 28,taken along the line 29-29;

FIGS. 30A-30D are side views illustrating a method of intravascularlydelivering the stimulation lead of FIG. 28 into, and occluding, acerebral blood vessel of a patient;

FIG. 31 is a plan view of yet another stimulation lead constructed inaccordance with a preferred embodiment of the present invention;

FIG. 32 is a cross-sectional view of the stimulation lead of FIG. 31,taken along the line 32-32;

FIGS. 33A-33B are side views illustrating a method of intravascularlydelivering the stimulation lead of FIG. 31 into, and occluding, acerebral blood vessel of a patient;

FIG. 34 is a plan view of a stimulation catheter, particularly showingan electrode basket electrode structure in an expanded three-dimensionalstate;

FIG. 35 is a plan view of the stimulation catheter of FIG. 34,particularly showing the basket electrode structure in a compactcollapsed state;

FIG. 35A is a cross-sectional view of the stimulation catheter of FIG.34, taken along the line 35A-35A;

FIGS. 36A-36E are side views illustrating a method of intravascularlydelivering and deploying the basket electrode structure of FIG. 34within a ventricular cavity of a patient's brain;

FIG. 37 is a plan view of yet another stimulation lead constructed inaccordance with a preferred embodiment of the present invention;

FIG. 38 is a plan view of the stimulation lead of FIG. 37, wherein astent is particularly shown deployed;

FIG. 39 is a cross-sectional view of the stimulation lead of FIG. 37,taken along the line 39-39;

FIG. 40 is a cross-sectional view of the stimulation lead of FIG. 37,taken along the line 40-40;

FIG. 41 is a cross-sectional view of the stimulation lead of FIG. 38,taken along the line 41-41;

FIGS. 42A-42D are side views illustrating a method of intravascularlydelivering the stimulation lead of FIG. 37 into a cerebral blood vesselof a patient;

FIG. 43 is a perspective view of still another brain stimulation kitarranged in accordance with a preferred embodiment of the presentinvention;

FIG. 44 is a cross-sectional view of a delivery catheter used in thestimulation kit of FIG. 43, taken along the line 44-44;

FIGS. 45A-45C are side views illustrating a method of intravascularlydelivering a stimulation lead into a cerebral blood vessel within thebrain of a patient using the kit of FIG. 43;

FIG. 46 is a plan view of a stimulation catheter, particularly showing ahelical electrode structure in an expanded three-dimensional state;

FIG. 47 is a plan view of the stimulation catheter of FIG. 46,particularly showing the helical electrode structure in a compactcollapsed state;

FIG. 48 is a cross-sectional view of the stimulation catheter of FIG.46, taken along the line 48-48;

FIGS. 49A-49C are side views illustrating a method of intravascularlydelivering the catheter of FIG. 47 into a cerebral blood vessel withinthe brain of a patient;

FIG. 50 is a plan view of yet another brain stimulation kit arranged inaccordance with a preferred embodiment of the present invention;

FIG. 51 is a cross-sectional view of the delivery catheter used in thestimulation kit of FIG. 50, taken along the line 51-51;

FIGS. 52A-52H are side views illustrating a method of intravascularlydelivering a stimulation lead within the sub-arachnoid space of apatient using the kit of FIG. 50;

FIG. 53 is a plan view of yet another brain stimulation kit arranged inaccordance with a preferred embodiment of the present invention;

FIG. 54 is a cross-sectional view of the delivery catheter used in thestimulation kit of FIG. 53, taken along the line 54-54;

FIGS. 55A-55D are side views illustrating a method of intravascularlydelivering a stimulation lead within the sub-arachnoid space of apatient using the kit of FIG. 53;

FIG. 56 is a plan view of yet another brain stimulation kit arranged inaccordance with a preferred embodiment of the present invention;

FIG. 57 is a cross-sectional view of the delivery catheter used in thestimulation kit of FIG. 56, taken along the line 57-57; and

FIGS. 58A-58C are side views illustrating a method of intravascularlydelivering a stimulation lead within the sub-arachnoid space of apatient using the kit of FIG. 56.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, an intravascular brain stimulation system 10constructed in accordance with one preferred embodiment of the presentinvention is shown. In its simplest form, the stimulation system 10generally comprises an electrical stimulation electrode lead 12configured to be intravascularly implanted within a selected region of apatient's brain, and an implantable electrical stimulation source 14configured for delivering stimulation energy to the stimulation lead 12.

The stimulation electrode lead 12 comprises a flexible electricallyconductive wire 16 and a single electrode 18 mounted at the distal endof the wire 16 using suitable connection means, such as soldering orwelding. In the illustrated embodiment, the electrode 18 iscylindrically shaped and has a size that allows it to be deliveredthrough a delivery catheter, as will be described in further detailbelow. The wire 16 comprises an electrically conductive core with anouter insulative layer. The length of the wire 16 is preferably sized toextend from the selected stimulation site in the brain to the implantlocation of the stimulation source 14. For example, if the stimulationsource 14 is to be implanted in the chest region of the patient, thelength of the wire 16 may be in the range of 50 cm to 100 cm. If,however, the stimulation source 14 is to be implanted in the abdomen orgroin area of the patient, the length of the wire 16 may be in the rangeof 150 cm to 300 cm. The electrode 18 is composed of a biocompatible andelectrically conducting material, such as copper alloy, platinum,stainless steel, or nitinol. The electrically conducting material of theelectrode 18 can be further coated with platinum-iridium or gold toimprove its conduction properties, biocompatibility, and radiopacity. Toprevent blood clotting, the electrode lead 12 can be optionally coatedwith a non-thrombogenic agent.

Referring to FIG. 2, an alternative embodiment of a stimulationelectrode lead 12′ is shown. The stimulation lead 12′ is similar to thepreviously described stimulation lead 12, with the exception that itcomprises a pair of electrodes 18 (a proximal electrode 18(1) and adistal electrode 18(2)) and a pair of signal wires 16 respectivelycoupled to the pair of electrodes 18. The electrode pair 18 can besuitably formed, e.g., by mounting a pair of ring electrodes around anelectrically insulative cylindrical core 20, or by coating thecylindrical core 20 with electrically conductive material. The signalwires 16 extend through the cylindrical core 20 into contact with therespective electrodes 18(1) and 18(2). Thus, it can be appreciated thatthe stimulation lead 12′, by itself, can be operated in a bipolar mode.This is in contrast to the stimulation lead 12, which can be operated ina monopolar mode, or alternatively, can be operated in a bipolar mode inconjunction with another stimulation lead 12, as will be described infurther detail below.

Referring back to FIG. 1, the implantable stimulation source 14 isdesigned to deliver electrical pulses to the stimulation lead 12 inaccordance with programmed parameters. In the preferred embodiment, thestimulation source 14 is programmed to output electrical pulses havingamplitudes varying from 0.1 to 20 volts, pulse widths varying from 0.02to 1.5 milliseconds, and repetition rates varying from 2 to 2500 Hertz.In the illustrated embodiment, the stimulation source 14 takes the formof a totally self-contained generator, which once implanted, may beactivated and controlled by an outside telemetry source, e.g., a smallmagnet. In this case, the pulse generator has an internal power sourcethat limits the life of the pulse generator to a few years, and afterthe power source is expended, the pulse generator must be replaced.Generally, these types of stimulation sources 14 may be implanted withinthe chest or abdominal region beneath the skin of the patient.Alternatively, the implantable stimulation source 14 may take the formof a passive receiver that receives radio frequency (RF) signals from anexternal transmitter worn by the patient. In this scenario, the life ofthe stimulation source 14 is virtually unlimited, since the stimulationsignals originate from the external transmitter. Like the self-containedgenerators, the receivers of these types of stimulation sources 14 canbe implanted within the chest or abdominal region beneath the skin ofthe patient. The receivers may also be suitable for implantation behindthe ear of the patient, in which case, the external transmitter may beworn on the ear of the patient in a manner similar to that of a hearingaid. Stimulation sources, such as those just described, are commerciallyavailable from Medtronic, Inc., located in Minneapolis, Minn. Furtherdetails regarding the construction of a stimulation source for thepurpose of treating neurological disorders is disclosed in U.S. Pat. No.5,716,377, which is expressly incorporated herein by reference.

In optional embodiments, the stimulation source 14 provides automatedfeedback for recording and stimulation to control such neurologicaldisorders as Epileptic seizures. Further details on the use of feedbackto control Epileptic seizures and other disorders are disclosed in U.S.Pat. No. 5,716,377, which has previously been incorporated herein byreference, and U.S. Pat. No. 6,360,122, which is expressly incorporatedherein by reference.

As illustrated in FIGS. 3-5, the electrical path of the stimulationsignals generated by the stimulation system 10 will depend on the mannerin which the stimulation source 14 is connected to the signal wires 16of the stimulation leads 12. For example, FIG. 3 illustrates afour-channel monopolar arrangement, wherein the positive terminal of thestimulation source 14 is coupled in parallel to signal wires 16 of fourstimulation leads 12(1)-(4). In this case, the electrical stimulationsignals will travel from the four electrodes 18 located on therespective stimulation leads 12, through the brain tissue, and back tothe electrically conductive casing of the stimulation source 14 remotelyimplanted in the patient's body.

FIG. 4 illustrates a bipolar arrangement, wherein the positive terminalof the stimulation source 14 is coupled in parallel to the signal wires16 of the first and third stimulation leads 12(1) and 12(3), and thenegative terminal of the stimulation source 14 is coupled in parallel tothe signal wires 16 of the second and fourth stimulation leads 12(2) and12(4). In this case, the electrical stimulation signals will travel fromthe electrode 18 of the first stimulation lead 12(1), through the braintissue, to the electrode 18 of the second stimulation lead 12(2), andfrom the third stimulation lead 12(2), through the brain tissue, to theelectrodes 18 of the second and fourth stimulation leads 12(2) and12(4).

FIG. 5 illustrates a four-channel bipolar arrangement, wherein thepositive terminal of the stimulation source is coupled in parallel tothe distal electrodes 18(2) of the four stimulation leads 12′(1)-12′(4),and the negative terminal of the stimulation source is coupled inparallel to the proximal electrodes 18(1) on the respective stimulationleads 12′(1)-12′(4). In this case, the electrical stimulation signalswill travel from the distal electrodes 18(2) of the respectivestimulation leads 12′(1)-12′(4), through the brain tissue, to therespective proximal electrodes 18(1) located on the same stimulationleads 12′(1)-12′(4).

Referring now to FIG. 6, an intravascular brain stimulation kit 30arranged in accordance with one preferred embodiment of the presentinvention is illustrated. The brain stimulation kit 30 comprises aplurality of the previously described electrical stimulation electrodeleads 12 (or stimulation electrode leads 12′) and implantable electricalstimulation source 14, a delivery catheter 32 configured forintravascularly delivering the electrical stimulation leads 12 intoselected blood vessels within the patient's brain, a guidewire 34configured for guiding the delivery catheter 32 into the selected bloodvessels, and detachable pusher elements 36 configured for deploying thestimulation leads 12 from the delivery catheter 32 into selected regionswithin the blood vessels.

Each pusher element 36 is mechanically coupled to the electrode 18 onthe respective stimulation lead 12. The pusher element 36 is axiallyrigid, so that the electrode 18 can be introduced through the catheter32, yet laterally flexible to allow the pusher element 36 to bend aroundthe natural curves within the patient's vasculature. In the illustratedembodiment, the pusher element 36 can be selectively detached from theelectrode 18 (once properly placed) using an electrolytic arrangement.

In particular, as illustrated in FIG. 7, the pusher element 36 comprisesan electrically conductive core wire 38 composed of a material that willelectrolytically dissolve in an aqueous fluid medium, such as blood,saline solution, or other bodily fluid. Materials that are capable ofelectrolytically dissolving are steel, stainless steel, nickel, andnickel/titanium alloys. The electrode 18 may be suitably coupled to thedistal end of the core wire 38 using means, such as crimping, soldering,or welding. The pusher element 36 further comprises an insulative sleeve40 that, with the exception of a small sacrificial portion 42 justproximal to the mounted electrode 18, covers the core wire 38. Thelength of the sacrificial portion 42 is preferably small. For instance,it may be as short as 0.010 inches, and typically no longer than 0.150inches in length. The insulative sleeve 40 is composed of a materialthat will not decompose prior to the sacrificial portion 42 of the corewire 38. For example, the insulative sleeve 40 may be composed ofpolytetrafluoroethylene, fluoropolymers, polyurethane, parylene,polyethylene, polypropylene, polyethylene terephthalate, or other knownsuitable, typically polymeric, material. Thus, it can be appreciatedthat when electrical current is delivered through the core wire 38,while the distal end of the pusher element 36 is exposed to blood, thesacrificial portion 42 of the core wire 38 will disintegrate, therebyreleasing the electrode 18. Additional details regarding the use ofpusher wires with electrolytic detachment means are disclosed in U.S.Pat. No. 6,589,230, which is expressly incorporated herein by reference.

In alternative embodiments, pusher wires with mechanical detachmentmechanisms can be used to selectively detach the electrode 18. Forexample, U.S. Pat. Nos. 5,234,437, 5,250,071, 5,261,916, 5,304,195,5,312,415, and 5,350,397, which are expressly incorporated herein byreference, disclose such mechanically detachable means.

Referring back to FIG. 6, the delivery catheter 32 comprises anelongate, flexible, catheter body 44 and a guidewire lumen 46 (shown inFIG. 8) extending the length of the catheter body 44. The guidewirelumen 46 is configured to singly receive the guidewire 34 andstimulation electrode lead 12. The delivery catheter 32 furthercomprises a proximal adapter 48 suitably mounted on the proximal end ofthe catheter body 44. The proximal adapter 48 comprises a guidewire port49 out which the guidewire 34 may extend when the delivery catheter 32is introduced over the guidewire 34. The guidewire port 49 also servesas a port through which the stimulation leads 12 can be introducedthrough the delivery catheter 32.

The catheter body 44 is composed of a medically acceptable material,preferably a nondistensible polymer having the appropriate mechanicalproperties. Preferred materials include polyethylene, polyester,polypropylene, polyimide, polyvinyl chloride, ethylvinyl acetate,polyethylene terephthalate, polyurethane, PEBAX, fluoropolymers, andtheir mixtures and block or random copolymers. The catheter body 32preferably has a relatively stiff proximal segment 50, which makes upbetween 70%-95% of the total length of the catheter body 44, and arelatively flexible distal segment 52, which makes up the remaining5%-30% of the length of the catheter body 44.

The guidewire lumen 46 of the catheter 32 preferably has a diameter ofbetween 2-50 mils, but ultimately will be sized to allow the electrode18 and guidewire 34 to be introduced therethrough. The outer diameter ofthe catheter body 44 is preferably between 8-80 mils, but ultimatelywill be sized such that blood flow is not occluded within the smallestblood vessel through which the delivery catheter 32 will be introduced.For example, the vessel site may be within a small diameter vesselhaving a 2-5 mm diameter and accessible by way of a tortuous vesselpath, which may involve sharp vessel turns and multiple vessel branches.In this case, the catheter 32 preferably has a small, flexibleconstruction with a diameter of less than 40 mil, and preferably between8-30 mils. The length of the catheter body 44 will typically be from50-300 cm, depending on the total linear length of the blood vesselsthat the delivery catheter 32 must traverse from its entry point intothe patient's vasculature to the intended delivery site of the electrode18.

Preferably, the guidewire lumen 46 of the delivery catheter 32 is largeenough to simultaneously fit the guidewire 34 and the multiple signalwires 16 from the stimulation leads 12. In this manner, a multitude ofthe stimulation leads 12 can be delivered to selected region in thebrain without having to completely remove the delivery catheter 32 fromthe patient's vasculature, as will be described in further detail below.

Alternatively, as illustrated in FIG. 9, the delivery catheter 32 has adedicated stimulation lead delivery lumen 54. This delivery lumen 54 ispreferably sized to fit an electrode 18, so that multiple stimulationleads 12 can be delivered by sequentially introducing the stimulationleads 12 through the dedicated delivery lumen 54. To facilitate separateintroduction of a stimulation lead 12 through the delivery catheter 32,the proximal adapter 48, in addition to having a guidewire port 49, hasa separate signal wire port (not shown).

Alternatively, as illustrated in FIG. 10, the delivery catheter 32 canhave multiple dedicated stimulation lead delivery lumens 56. Again, thedelivery lumens 56 are preferably sized to fit the respective electrodes18. In this case, the multiple stimulation leads 12 can be sequentiallydeployed from the respective delivery lumens 56 without mechanicallyinterfering with each other. To facilitate separate introduction of thestimulation leads 12 through the delivery catheter 32, the proximaladapter 48, in addition to having a guidewire port 49, has an equalnumber of separate signal wire ports (not shown).

Alternatively, as illustrated in FIGS. 11 and 12, the delivery catheter32 can have multiple dedicated stimulation lead delivery lumens 56 thatdistort, so that the diameter of the delivery catheter 32 can bereduced. In particular, the delivery catheter 32 comprises outer tube 51composed of a suitable non-compliant material, and an inner tube 53,which forms the guidewire lumen 46 and is composed of a similarnon-compliant material. The delivery catheter 32 further comprises acylindrical body 55 formed between the outer and inner tubes 51 and 53.The cylindrical body 55 is composed of a suitable compliant material,such as silicone. The delivery lumens 56 are formed through thecylindrical body 55, such that the delivery lumens 56 will expand in thepresence of a radially outward force and contract in the presence of aradially inward force.

In this manner, the lumens 56 can be dimensioned smaller than theelectrodes 18 of the stimulation leads 12, thus minimizing the diameterof the catheter 32. Because the lumens 56 are capable of expanding inthe presence of an outward radial force, however, a lumen 56 will expandto accommodate an electrode 18 as it is delivered through the lumen 56.At the same time, the inner tube 53 will be displaced away from theexpanded lumen 56, thereby creating inwardly radial pressure on thelumen 56 opposite the expanding lumen 56, as illustrated in FIG. 12. Asa result, the opposite lumen 56, which does not house an electrode 18 atthis time, will distort in the presence of the radial force exerted bythe inner tube 53. Thus, the distortion of a delivery lumen 56 willcompensate for the expansion of the oppositely disposed delivery lumen56, and vice versa.

Referring back to FIG. 6, the guidewire 34 may have any suitableconstruction for guiding the delivery catheter 32 to its intended sitein the brain. Typically, the length of the guidewire 34 is at leastabout 10-50 cm longer than the length of the catheter 32, such that thedistal end of the guidewire 34 can be extended several centimeters ormore beyond the distal end of the delivery catheter 32, while allowingthe proximal end of the guidewire 34 to be manipulated, such as bytorqueing. The proximal end of the guidewire 34 is equipped with ahandle 58 for applying torque to the wire during catheter operation. Theguidewire 34 may optionally include radio-opaque bands (not shown) forvisualization under fluoroscopy. Additional details regarding thestructure and dimensions of guidewires suitable for guiding cathetersinto the vasculature of the brain are disclosed in U.S. Pat. No.6,074,507, which is expressly incorporated herein by reference.

Having described the structure of the intravascular brain stimulationkit 30, a preferred method of installing the intravascular brainstimulation system 10 within a patient's body in order to treat adiagnosed neurological disorder within the brain will now be described.

The routing and placement of the brain stimulation system 10 willultimately depend on the portion of the brain that is to be treated. Forexample, the cortex of the brain or the deep brain can be electricallystimulated to provide post-stroke rehabilitation (from hemorrhagicstroke, ischemic stroke or head/brain trauma), Parkinson's Disease,Essential Tremor, Huntington's Disease, Alzheimer's Disease, Epilepsy,depression, obsessive compulsive disorder, schizophrenia, andneuropathic pain. Any lobe of the cortex or deep brain can bestimulated. Preferably, for the cortical region of the brain, the motorstrip, sensor strip, and premotor cortex should be stimulated. For thedeep brain region, the anterior thalamus, ventrolateral thalamus (Thal),internal segment of globus pallidus (GPi), substantia nigra parsreticulata (SNr), subthalamic nucleus (STN), external segment of globuspallidus (GPe), neostriatum, cingulate, and cingulate gyrus should bestimulated.

The spheno palatine ganglion (SPG), which can control the amount ofblood flow to the brain and the permeability of the blood brain barrier,may also be stimulated, e.g., to hyperperfuse a hemisphere of the braindamaged as a result of an ischemic event, such as a stroke, or to helpmetabolize amlyoid plaques caused by Alzheimer's Disease and prevent theoccurrence of vaso-spasms, both achieved through increased blood flow tothe brain. Lastly, the SPG can be stimulated to facilitate the openingof the blood-brain barrier, enabling better uptake of drugs to thebrain. These drugs could be delivered in a variety of methods (e.g.orally, intravenously, or via direct injection into the penumbra) andcould be used to treat a variety of neurologically related maladies(stroke, epilepsy, Parkinson's, tumors, essential tremor, Alzheimer's,etc.).

A stimulation lead can be delivered to any one of a number of vessels inorder to place the active portion of the stimulation lead adjacent thecortical tissue to be stimulated. Examples of veins providing access tothe cortex include the superior sagittal sinus, any of the superiorcerebral veins branching from the superior sagittal sinus (e.g., thelacuna, frontopolar vein, anterior frontal vein, posterior frontal vein,precentral vein, central vein, anterior parietal vein, posteriorparietal vein, and occipital vein), superior sylvian vein, vein ofLabbe, vein of Trolard, inferior sagittal sinus, and any inferiorcerebral veins branching off of the inferior sagittal sinus, transversesinus, and meningeal sinus. Examples of arteries providing access to thecortex include any of the branches off of the external carotid,maxillary, or meningeal arteries.

Examples of veins providing access to the deep brain include theinferior sagittal sinus, pericallosal sinus, cavernous sinus, sphenoidsinus, temperal basal vein, and occipital veins. Examples of arteriesproviding access to the deep brain include any branches off of theinternal carotid or vertebral arteries. Examples of veins providingaccess to the SPG include the superficial temporal veins and the facialvein. Examples of arteries providing access to the SPG include themaxillary artery, descending palatine artery, and facial artery.

The jugular and femoral veins can be used as intrasvascular accesspoints from which stimulation leads can be delivered to theabove-described veins, and the carotid or femoral arteries can be usedas intrasvascular access points from which the stimulation leads can bedelivered to the above-described arteries.

With reference now to FIGS. 13A-13H, an exemplary method used to deliverstimulation leads 12 to the superior cerebral veins 206 branching off ofthe superior sagittal sinus 204, which runs along the top of the cortex202, will now be described. First, from a remote access site, such asthe inner jugular vein or femoral vein (not shown), the guidewire 34 isrouted through the superior sagittal sinus 204 and into a selectedsuperior cerebral vein 206 until the distal end of the guidewire 34extends past a selected stimulation site 208 (FIG. 13A). To facilitatethe correct routing and placement of the guidewire 34, diagnosticimaging, such as fluoroscopy, magnetic resonance imaging (MRI), andcomputer tomography (CT), is preferably used to track the distal end ofthe guidewire 34. As will be described in further detail below, theaccess site into the vasculature will ultimately depend on the selectedimplantation site of the stimulation source 14. For example, if thestimulation source 14 is to be implanted within the chest or clavicalregion, or behind the ear, of the patient, the jugular vein should beselected as the access point. If, on the other hand, the stimulationsource 14 is to be implanted within the abdominal or groin region of thepatient, the femoral vein should be selected as the access point.

Next, the delivery catheter 32 is introduced over the guidewire 34 untilthe distal end of the catheter 32 is just proximal to the selectedstimulation site 208 (FIG. 13B). Once proper placement of the catheter32 is achieved, the guidewire 34 is removed from guidewire lumen 46 viathe proximal adapter 48 of the delivery catheter 32, and the stimulationlead 12 and associated pusher element 36 are inserted into the deliverycatheter 32 via the proximal adapter 48, and then distally advancedthrough the delivery catheter 32 until the distal end of the stimulationlead 12 deploys out from the distal end of the catheter 32 adjacent theselected stimulation site 208 (FIG. 13C). Next, the pusher element 36 iselectrolytically detached from the electrode 18 and removed from thedelivery catheter 32 via the proximal adapter 48 (FIG. 13D). Aspreviously discussed, detachment of the pusher element 36 can beaccomplished by applying an electrical current to the proximal end ofthe core wire 16, which as previously described above, causes thesacrificial joint 42 (shown in FIG. 7) on the core wire 38 to dissolvein the presence of blood.

Assuming that additional stimulation leads 12 are to be placed withinthe brain 200, the delivery catheter 32 can be pulled back in theproximal direction until its distal end resides within the superiorsagittal sinus 204, and the guidewire 34 can then be introduced throughthe delivery catheter 32 via the proximal adapter 48, and manipulatedinto another superior cerebral vein 206′, such that the distal end ofthe guidewire 34 is located distal to another selected stimulation site208′ (FIG. 13E). Notably, the signal wire 16 of the first stimulationlead 12 will still be located within the guidewire lumen 46 duringadvancement of the guidewire 34 therethrough, and thus, the profile ofthe signal wire 16 should be small enough, such that the guidewire 34and the signal wire 16, as well as subsequent signals wire 16, cansimultaneously reside within the guidewire lumen 46. It should be notedthat it is possible for the first stimulation lead 12 to move when thedelivery catheter 32 is pulled back in the proximal direction. In thiscase, it may be desirable to detach the pusher element 36 from the firstelectrode 18 after the delivery catheter 32 has been pulled back. Inthis manner, the pusher element 36 can be used to stabilize theelectrode 18 while the delivery catheter 36 is displaced.

Alternatively, prior to reintroduction of the guidewire 34, the catheter32 can be completely removed from the patient's vascularly, whilemaintaining the electrode 18 within the selected superior cerebralbrain. The catheter 32 can then be reinserted into the patient'svascular, and then the guidewire 34 can be introduced through theguidewire lumen 46, so that the distal end of the guidewire 34 resideswithin a location distal to the other stimulation site 208.

In any event, the delivery catheter 32 is then advanced over theguidewire 34 until the distal end of the catheter 32 is placed adjacentthe other selected stimulation site 208′, the guidewire 34 is removedfrom the delivery catheter 32, another stimulation lead 12 with anotherpusher element 36 is advanced through the guidewire lumen 46 until theelectrode 18 is adjacent the other selected stimulation site 208, andthe pusher element 36 is then detached from the electrode 18 by applyingan electrical current to the proximal end of the core wire 16 (FIG.13F). The steps illustrated in FIGS. 13E-13F can then be repeated ifadditional stimulation leads 12 are to be placed within the brain 200.In the illustrated case, a total of three stimulation leads 12 areimplanted within the superior veins branching from the superior sagittalsinus (FIG. 13G). After all of the stimulation leads 12 have beendeployed within the brain 200, the delivery catheter 32 is removed fromthe superior sagittal sinus 204. It can be appreciated from theforegoing process that if the placement of multiple stimulation leads 12within the brain 200 is desired, the most distal stimulation leads 12should be placed first in order to minimize disturbance of thestimulation leads 12 as the delivery catheter 32 is pulled in theproximal direction.

Depending on the nature of the neurological disorder and goals of theoperation, the stimulation leads 12 may be left within the brain eitheracutely (i.e., only during an operation and then removed after theoperation has been completed), chronically, or sub-chronically (i.e.,less than six months).

In an alternative method, the delivery catheter 32 illustrated in FIG. 9can be used. In this case, after the distal end of the delivery catheter32 has been placed proximal to the selected stimulation site 208, in themanner illustrated in FIG. 13B, the guidewire 34 is retracted to aposition proximal to the selected stimulation site 208 to provideclearance for deployment of the stimulation lead 12 (FIG. 14A). Notably,since the guidewire lumen 46 need not be capable of additionallyaccommodating stimulation leads 12, the guidewire 34 will not need to beremoved from the delivery catheter 32 as otherwise illustrated in FIG.13C. Next, the stimulation lead 12 is distally advanced through thededicated delivery lumen 54 (shown in FIG. 9) of the catheter 32 untilthe distal end of the stimulation lead 12 deploys out from the distalend of the catheter 32 adjacent the selected stimulation site 208 (FIG.14B). Next, the pusher element 36 is detached from the electrode 18 andremoved from the delivery catheter 32 via the proximal adapter 48 (FIG.14C).

Assuming that additional stimulation leads 12 are to be placed withinthe brain 200, the delivery catheter 32 can be pulled back in theproximal direction until its distal end resides within the superiorsagittal sinus 204 (FIG. 14D), and the guidewire 34 can be manipulatedinto another superior cerebral vein 206′, such that the distal end ofthe guidewire 34 is located distal to another selected stimulation site208′ (FIG. 14E). The delivery catheter 32 can then be advanced over theguidewire 34 until the distal end of the delivery catheter 32 is placedadjacent the other selected stimulation site 208′, the guidewire 34 canbe retracted proximal to the other selected stimulation site 208′,another stimulation lead 12 with another pusher element 36 can beadvanced through the dedicated delivery lumen 54 until the electrode 18is adjacent the other selected stimulation site 208′, and the pusherelement 36 can then be detached from the electrode 18 by applying anelectrical current to the proximal end of the core wire 16 (FIG. 14F).The steps illustrated in FIGS. 14A-14F can then be repeated ifadditional stimulation leads 12 are to be placed within the brain 200.Notably, the dedicated delivery lumen 54 should be large enough toaccommodate the electrode 18 of the currently deployed stimulation lead12, an associated pusher element 36, and the multiple signal wires 16 ofthe current and previously deployed stimulation leads 12.

In an alternative multi-stimulation lead deployment method, the deliverycatheters 32 illustrated in FIG. 10 or FIG. 11 can be used. In thiscase, the stimulation leads 12 are deployed from the delivery catheter32 in the same manner as the stimulation leads 12 are deployed from thepreviously described delivery catheter 32 illustrated in FIGS. 14A-14F,with the exception that all of the stimulation leads 12 can be deployedthrough the respective dedicated signal wire delivery lumens 56 (shownin FIGS. 10 and 11) of the delivery catheter 32. In this manner,previously deployed stimulation leads 12 will not be disturbed by thesubsequent introduction of the stimulation leads 12 through the deliverycatheter 32.

Whichever method is used to deploy the stimulation leads, the proximalends of the implanted stimulation leads 12 will remain outside of thepatient's body after the stimulation deployment process is completed,and in particular, will extend from the vascular access point, e.g., theinternal jugular vein or femoral vein. These exposed ends of thestimulation leads 12 can be subcutaneously routed a short distance tothe clavical or chest region or behind the ear of the patient (in thiscase where the jugular vein is the access point) or the abdominal orgroin region of the patient (in the case where the femoral vein is theaccess point), where they can be coupled to the implanted stimulationsource 14, as illustrated in FIG. 15. Alternatively, the stimulationsource 14 may not be implanted, but rather located exterior to thepatient. e.g., during a non-chronic procedure. The electrodes 18 of thestimulation leads 12 are coupled in parallel to the positive terminal ofthe stimulation source 14 to form a monopolar arrangement, wherebyelectrical signals travel from the electrodes 18 to the electricallyconductive casing of the implanted stimulation source 14 when thestimulation source 14 is operated. As a result, the brain tissuecontained within a region 210 generally surrounding the selectedsuperior cerebral veins 206 is stimulated.

Using a stimulation lead implantation process similar to that describedabove, respective electrodes 18 of three stimulation leads 12 can beimplanted within the superior cerebral veins 206 branching from thesuperior sagittal sinus 204, and the respective electrodes 18 of threemore stimulation leads 12 can be implanted within the inferior cerebralveins 214 branching from the inferior sagittal sinus 212, as illustratedin FIG. 16. The stimulation leads 12 can be routed into the inferiorsagittal sinus 212 via the straight sinus 216 of the superior sagittalsinus 204. Again, the inner jugular vein or femoral vein can be used asthe access point to the patient's vasculature. As illustrated,electrodes 18 of the stimulation leads 12 located in the superiorcerebral veins 206 are coupled in parallel to the positive terminal ofthe stimulation source 14, and the electrodes of the stimulation leads12 located in the inferior cerebral veins 214 are coupled in parallel tothe negative terminal of the stimulation source 14. In this manner, abipolar arrangement is formed, whereby electrical signals travel fromthe electrodes 18 located in the superior cerebral veins 206 to theelectrodes 18 located in the inferior cerebral veins 214 when thestimulation source 14 is operated. As a result, the brain tissuecontained within a region 216 between the selected superior and inferiorcerebral veins is therapeutically stimulated.

Using a stimulation lead implantation process similar to that describedabove, respective bipolar electrodes 18(1) and 18(2) of threestimulation leads 12′ (shown in FIG. 2 can be implanted within thesuperior veins branching from the superior sagittal sinus, asillustrated in FIG. 17. Again, the inner jugular vein or femoral veincan be used as the access point to the patient's vasculature. Asillustrated, the distal electrodes 18(2) of the stimulation leads 12′are coupled in parallel to the positive terminal of the stimulationsource 14, and the proximal electrodes 18(1) of the stimulation leads12′ are coupled in parallel to the negative terminal of the stimulationsource 14. In this manner, a bipolar arrangement is formed, wherebyelectrical signals travel from the distal electrodes 18(2) to theproximal electrodes 18(1) on the stimulation leads 12′. As a result, thebrain tissue contained within a regions 218 between and surrounding theselected superior veins is therapeutically stimulated.

Referring now to FIG. 18, another intravascular brain stimulation kit 60arranged in accordance with another preferred embodiment of the presentinvention is illustrated. The brain stimulation kit 60 comprises aplurality of the previously described electrical stimulation electrodeleads 12 (or stimulation electrode leads 12′) and implantable electricalstimulation source 14 (not shown in FIG. 18), a delivery catheter 62configured for intravascularly delivering the electrical stimulationleads 12 into selected blood vessels within the patient's brain, thepreviously described guidewire 34, and a pusher element 64.

The delivery catheter 62 comprises an elongate, flexible, catheter body66 and a guidewire lumen 68, signal wire lumen 70, and pusher elementlumen 72 (shown in FIG. 19) longitudinally extending through thecatheter body 66. The catheter body 66 may be composed of the samematerial and have the same dimensions as the previously describedcatheter body 44. The guidewire lumen 68 houses the guidewire (notshown), the signal wire lumen 70 houses the signal wires 16 of thestimulation leads 12, and the pusher element lumen 72 houses theelectrodes 18 of the stimulation leads 12 and the pusher element 64. Thedelivery catheter 62 comprises a proximal adapter 74 suitably mounted onthe proximal end of the catheter body 66. The proximal adapter 74comprises separate guidewire, signal wire, and pusher element ports (allnot shown).

Unlike the previously described pusher elements 36, the pusher element64 is not mechanically coupled to the electrodes 18, but rather onlyoperates to push the electrodes 18 out from the pusher element lumen 72of the catheter 62. To this end, the pusher element 64 may simply takethe form of a rod composed of an axially rigid, yet laterally flexiblematerial.

The stimulation leads 12 can be delivered to selected stimulation siteswithin the patient's brain in the same manner as the stimulation leads12 were delivered in FIGS. 14A-14F, with the exception that thestimulation leads 12 are pre-loaded within the delivery catheter 62 andthe pusher element 64 need not be actively detached from the electrodes18.

Although the delivery catheter 62 is shown in FIG. 18 as having a singlesignal wire lumen 70, multiple signal wire lumens can be provided. Forexample, FIG. 20 illustrates the delivery catheter 62 with a dedicatedsignal wire lumen 70 for each signal wire 16 (in this case, two).

Although the previously described kits have included delivery cathetersfor delivering the stimulation leads to the selected stimulation siteswithin the brain, stimulation leads can be delivered without deliverycatheters. For example, FIG. 22 illustrates a brain stimulation kit 90that comprises a plurality of electrical stimulation electrode leads 92,and the previously described implantable electrical stimulation source14 (not shown in FIG. 22), guidewire 34, and pusher element 36.

Like the previously described stimulation electrode lead 12, thestimulation electrode lead 92 illustrated in FIG. 22 comprises aflexible electrically conductive wire 94 and a single electrode 96mounted at the distal end of the wire 94. Unlike the previouslydescribed stimulation electrode lead 12, however, the electrode 96comprises a lumen 98 sized to receive the guidewire 34, such that theelectrode 18 can longitudinally slide along the guidewire 34. Theelectrode 96 is bullet-shaped, i.e., it is generally shaped as acylinder with a tapered distal tip. In this manner, the exposedelectrode 96 can be introduced through the patient's vasculature withoutthe risk of causing tissue trauma.

Referring now to FIGS. 23A-23E, a preferred method of delivering thestimulation leads 92 to a selected region of the patient's brain willnow be described. As with the previously described exemplary method, thestimulation leads 92 are placed within the superior cerebral veins 206branching off of the superior sagittal sinus 204, so that the cortex 202of the brain 200 can ultimately be electrically stimulated to treat aneurological disorder within the patient.

Like in the previous method, the guidewire 34 is routed through thesuperior sagittal sinus 204 and into a selected cerebral vein 206 untilthe distal end of the guidewire 34 is proximal to a selected stimulationsite 208 (FIG. 23A). The jugular vein or femoral vein, for examples, canbe used as the access point into the patient's vasculature. Once properplacement of the guidewire 34 is achieved, the electrode 96 of thestimulation lead 92 is threaded over the guide wire 34, and distallyadvanced up the guidewire 34 by pushing the pusher element 36 until theelectrode 96 is placed adjacent the selected stimulation site 208 (FIG.23B). Next, the pusher element 36 is electrolytically detached from theelectrode 96 and removed from the patient (FIG. 23C).

Assuming that additional stimulation leads 92 are to be placed withinthe brain 200, the guidewire 34 can be pulled back in the proximaldirection, and then manipulated into another superior cerebral vein206′, such that the distal end of the guidewire 34 is located proximalto another selected stimulation site 208′ (FIG. 23D). Anotherstimulation lead 92 with an associated pusher element 36 can be distallyadvanced up the guidewire 34 until the electrode 96 is adjacent theother selected stimulation site 208′, and the pusher element 36 can thenbe detached from the electrode 96 and removed from the patient (FIG.23E). The steps illustrated in FIGS. 23D and 23E can then be repeated ifadditional stimulation leads 92 are to be placed within the brain 200.The guidewire 34 is then removed from the patient's body, and theproximal ends of the signal wires 94, which extend from the patient'sbody (e.g., from the access point of the jugular vein or femoral vein),are then connected to the implanted stimulation source 14 (FIG. 23F).

Although all the previously described stimulation leads have beendelivered to the selected stimulation sites using either a separatedelivery catheter, a separate guidewire, or both, stimulation leads cantake the form of a guidewire or catheter to minimize the need foradditional delivery elements. For example, FIGS. 24 and 25 illustrate astimulation lead 102 that takes the form of a guidewire. The guidewire102 comprises an elongated flexible shaft 104, a plurality of bipolarelectrode pairs 106 (comprising a proximal ring electrode 106(1) and adistal ring electrode 106(2)) mounted to the distal end of the shaft104, and an electrical connector 108 mounted to the proximal end of theshaft 104.

The shaft 104 is formed of an outer tubular member 110, an inner braidedtubular member 112, and a core member 114 that is disposed within theinner tubular member 112 and extends past the distal end thereof. Theshaft 104 further comprises a coil 116 secured to the distal end of thecore member 114 using suitable means, such as brazing, soldering, orbonding, and a rounded distal tip 118 secured to the distal extremity ofthe core member 114. The inner tubular member 112 comprises a pluralityof electrical conductors 120 that are distally connected to theelectrodes 106 and proximally connected to the connector 108. Thedimensions of the guidewire 102 are preferably the same as thedimensions of the guidewire 34 described above. Details regarding theconstruction of guidewires with electrodes are disclosed in U.S. Pat.No. 5,509,411, which is expressly incorporated herein by reference.

It can be appreciated that because the stimulation lead 102 takes theform of a guidewire that can be manipulated through the patient'scerebral vasculature, no other delivery mechanisms are required. As withthe previously described stimulation leads 12, the guidewire 102 can bedeployed into various vessels within the patient's brain 200, and can beconnected to an implanted stimulation source. For example, FIG. 26illustrates the guidewire 102 placed along the superior sagittal sinus204. In this case, the cortical brain tissue running along the superiorsagittal sinus 204 can be therapeutically stimulated by the conveyanceof stimulation energy between the distal and proximal electrodes 106(1)and 106(2) of the bipolar electrode pairs 106. FIG. 27 illustrates theguidewire 102 placed along a superior cerebral vein 206. In this case,the cortical brain tissue running along the superior cerebral vein 206can be therapeutically stimulated by the conveyance of stimulationenergy between the distal and proximal electrodes 106(1) and 106(2) ofthe bipolar electrode pairs 106.

In alternative embodiments, the electrodes 106 of the guidewire 102 maybe configured in a monopolar arrangement. In this case, the stimulationenergy may be conveyed through the cerebral tissue from the monopolarelectrodes to the casing of the implanted stimulation source. Or,alternatively, a second guidewire 106 can be placed into another vessel,such as the inferior sagittal sinus. In this case, the stimulationenergy may be conveyed through the cerebral tissue between the superiorand inferior sagittal sinuses.

FIG. 28 illustrates a stimulation lead 122 that takes the form of acatheter. The catheter 122 comprises an elongate, flexible, catheterbody 124, a plurality of ring electrodes 126, an inflatable balloon 128mounted on the distal end of the catheter body 124 proximal to theelectrodes 126, and a proximal adapter 130 mounted on the proximal endof the catheter body 124. The catheter body 124 can have the samedimensions and be composed of the same material as the previouslydescribed catheter body 44. The proximal adapter 130 comprises aguidewire port 132, an electrical connector 134, and an inflation port136.

The balloon 128 can be transformed from a deflated state into aninflated state (shown in phantom) by conveying an inflation medium, suchas saline, into the balloon. The balloon 128 is preferably about 0.5 to3 cm in length, and is composed of a wall that can be inflated by fluidsupplied through catheter body 124. The balloon wall is preferablycomposed of a polymeric material, and preferably an elastomeric,stretchable material such as silicone rubber, latex rubber, or polyvinylchloride, or alternatively, a non-stretchable film material, such aspolyethylene or polypropylene. Attachment of the balloon wall to thecatheter body 124 can be accomplished using suitable means, such asgluing, heat sealing or the like.

Referring further to FIG. 29, the catheter 122 has a guidewire lumen138, signal wire lumen 140, and inflation lumen 144 longitudinallyextending through the catheter body 124. The guidewire lumen 138 iscapable of receiving a guidewire (not shown). The signal wire lumen 140houses signals wires 142, which distally terminate at the electrodes 126and proximally terminate in the electrical connector 134 on the proximaladapter 130. Inflation medium may be conveyed into the inflation port136, through the inflation lumen 144, and into the interior of theballoon 128 in order to place the balloon 128 in its expanded state.

The catheter 122 can be used to stimulate brain tissue, whilechronically occluding the blood vessel in which it is disposed. In thismanner, the risk of a thromembolic stroke (mainly on the arterial side)is minimized. Preferably, chronic occlusion will be accomplished inblood vessels where there is a superfluous blood supply, such as themeningeal arteries.

A method of delivering the catheter 122 into a selected cerebral bloodvessel 212 within the brain 200, and chronically occluding the bloodvessel, will now be described with respect to FIGS. 30A-30D. First, aguidewire 34 is routed into the blood vessel 220 distal to a selectedstimulation site 222 (FIG. 30A). The jugular vein or artery or thefemoral vein or artery, for examples, can be used as the access pointinto the patient's vasculature. Once proper placement of the guidewire34 is achieved, the distal end of the catheter 122 is introduced overthe guidewire 34, and the catheter 122, while the balloon 128 is in itsdeflated state, is distally advanced up the guidewire 34 until thedistal end of the catheter 122 is adjacent the selected stimulation site222 (FIG. 30B). Next, inflation medium is conveyed up the catheter 122via the inflation port 136 on the proximal adapter 130, such that theballoon 128 is placed into its expanded state (FIG. 30C). In thismanner, the balloon 128 seals the blood vessel 220, thereby occludingthe blood flow through the blood vessel 220. The guidewire 34 is thenremoved from the catheter 122 via the guidewire port 132 on the proximaladapter 130, and thus, the patient's body, and the electrical connector134 on the proximal adapter 130, which extends from the patient's body(e.g., from the access point of the jugular vein or femoral vein), isthen connected to the implanted stimulation source 14 (FIG. 30D). Theinflation port 136 on the proximal adapter 130 is preferably sealed, sothat the balloon 128 is maintained in its expanded state. Alternatively,the blood flow through the blood vessel 220 is only temporarilyoccluded, in which case, the balloon 128 is placed back into itsdeflated state by conveying inflation medium out from the inflation port136.

FIG. 31 illustrates another stimulation lead 152 that takes the form ofa catheter. The catheter 152 is similar to the previously describedcatheter 122, with the exception that it uses ablation energy, ratherthan a balloon to occlude a cerebral blood vessel. In particular, thecatheter 152 comprises an elongate, flexible, catheter body 154, aplurality of the previously described ring electrodes 126, an ablationelement 158, such as a radio frequency (RF) electrode, mounted on thedistal end of the catheter body 154 proximal to the electrodes 126, anda proximal adapter 160 mounted on the proximal end of the catheter body154. The catheter body 154 can have the same dimensions and be composedof the same material as the previously described catheter body 44. Theproximal adapter 160 comprises the previously described guidewire port132 and electrical connector 134, as well as an ablation port 166.

In addition to the previously described guidewire lumen 138 and signalwire lumen 140 in which there are disposed a guidewire (not shown) andsignal wires 142, respectively, the catheter 152 further comprises anablation lumen 164 longitudinally extending through the catheter body154. The ablation lumen 164 houses an ablation wire 166, which distallyterminates at the ablation element 158 and proximally terminates in theablation port 166 on the proximal adapter 360.

Like the previously described catheter 122, the catheter 152 can be usedto stimulate brain tissue, while chronically occluding the blood vesselin which it is disposed. A method of delivering the catheter 152 into aselected cerebral blood vessel 220 within the brain 200, and chronicallyoccluding the blood vessel, will now be described with respect to FIGS.33A-33B. Once the guidewire 34 is properly located distal to theselected stimulation site 222 (as previously shown in FIG. 30A), thedistal end of the catheter 152 is introduced over the guidewire 34, andthe catheter 152 is distally advanced up the guidewire 34 until thedistal end of the catheter 152 is adjacent the selected stimulation site222 (FIG. 33A). Next, a source of ablation energy (not shown) isconnected to the ablation port 166 on the proximal adapter 160, andablation energy is conveyed through the ablation wire 16 to the ablationelement 158. As a result, the surrounding vessel tissue is heated,causing the vessel wall to collapse around the distal end of thecatheter 152 (FIG. 33B). In this manner, the blood vessel 220 is sealedaround the catheter 152, thereby occluding the blood flow through theblood vessel 220. The guidewire 34 is then removed from the catheter 152via the guidewire port 132 on the proximal adapter 160, and thus, thepatient's body, and the electrical connector 134 on the proximal adapter160, which extends from the patient's body (e.g., from the access pointof the jugular vein or femoral vein), is then connected to the implantedstimulation source 14 in a manner similar to that shown in FIG. 30D.

Although the previously described stimulation leads have been locatedwithin the circulatory system of the cerebral vasculature, stimulationleads can also be placed within the ventricular system of the cerebralvasculature, and in particular within the ventricular cavity of thebrain. One embodiment that lends itself to the stimulation of braintissue via the ventricular cavity arranges stimulation electrode leadsinto an expandable-collapsible basket assembly.

FIGS. 34 and 35 illustrate such a catheter 172, which comprises anelongate flexible catheter body 174, a three-dimensional multiple basketelectrode structure 176 mounted to the distal end of the catheter body174, and an electrical connector 178 mounted to the proximal end of thecatheter body 174. The catheter body 174 can have the same dimensionsand be composed of the same material as the previously describedcatheter body 44.

The basket electrode structure 176 comprises a base member 180, an endcap 182, and plurality of flexible stimulation leads or splines 184 thatextend in a circumferentially spaced relationship between the basemember 180 and end cap 182. The splines 184 are preferably made of aresilient inert material, like Nitinol metal or stainless steel. Thesplines 184 are connected between the base member 180 and the end cap182 in a resilient, pretensed condition, to bend and conform to thetissue surface that they contact. In the illustrated embodiment, eightsplines 184 form the basket electrode structure 176. Additional or fewersplines 184, however, could be used to form the basket electrodestructure 176.

The splines 184 carry an array of electrodes 186. In the illustratedembodiment, each spline 184 carries eight electrodes 186. Of course,additional or fewer electrodes 186 can be used. The electrodes 186 canbe arranged in a monopolar or a bipolar arrangement. In the bipolararrangement, stimulation energy may flow between electrodes 18 on thesame spline or between electrodes on separate splines. The catheter 172comprises a signal wire lumen 188 (shown in FIG. 35A) longitudinallyextending through the catheter body 174. The signal wire lumen 188houses signals wires 190, which distally terminate at the electrodes 186and proximally terminate in the electrical connector 178.

A slideable guide sheath 192 is movable along the axis of the catheterbody 174 (shown by arrows in FIG. 34). Moving the sheath 192 in thedistal direction over the basket electrode structure 176, collapses itinto a compact, collapsed low profile state, as illustrated in FIG. 35.Moving the sheath 192 in the proximal direction away from the basketelectrode structure 176, allows it to spring open into athree-dimensional expanded state. Further details of the basketelectrode structure are disclosed in pending U.S. Pat. No. 5,647,870,which is expressly incorporated herein by reference.

A method of delivering the catheter 172 into a ventricular cavity 224within the brain 200 will now be described with respect to FIGS.36A-36E. First, a guidewire 34 is routed up the spinal canal 226 of thepatient until the distal end of the guidewire 34 is located within theventricular cavity 224 (FIG. 36A). Then, the guide sheath 192 isdistally advanced up the guidewire 34 until the distal end of the guidesheath 192 resides within the ventricular cavity 224 (FIG. 36B). Next,the guidewire 34 is removed from the guide sheath 192, and the basketelectrode structure 176 (shown in phantom) of the catheter 172 isinserted into the proximal end of the guide sheath 192, such that thebasket electrode structure 176 is placed into its collapsed state (FIG.36C). The basket electrode structure 176 is then introduced through theguide sheath 192 until the basket electrode structure 176 is deployedfrom the distal end of the guide sheath 192 into the ventricular cavity224 (FIG. 36D). As illustrated, the basket electrode structure 176assumes its three-dimensional expanded state, such that the electrodes186 are placed into stable contact with the ventricular cavity 224. Theguide sheath 192 is then removed from the patient's body, and theelectrical connector 178 of the catheter 172, which extends from thepatient's body, and in particular from the back of the patient, is thenconnected to an implanted stimulation source 14 (FIG. 36E). Depending onthe configuration of the electrodes 186 and the connection to thestimulation source 14, the brain tissue surrounding the ventricularcavity 224 can be electrically stimulated in a monopolar or bipolarmode.

Stimulation leads with vessel stabilization devices will now bedescribed. Referring to FIGS. 37 and 38, a stimulation lead 252 thattakes the form of stent catheter is illustrated. The catheter 252comprises an elongate, flexible, catheter body 254, a plurality of ringelectrodes 256, an inflatable balloon 258 (shown in phantom in FIGS. 37and 38) mounted on the distal end of the catheter body 254, a stent 260mounted to the distal end of the catheter body 254, and a proximaladapter 262 mounted on the proximal end of the catheter body 254. Thecatheter body 254 can have the same dimensions and be composed of thesame material as the previously described catheter body 44.

The balloon 258 can be transformed from a deflated state (FIG. 37) intoan inflated state (FIG. 38) by conveying an inflation medium, such assaline, into the balloon. Expansion of the balloon 258 will accordinglyexpand the stent 260. The balloon 258 is preferably composed of asuitable non-compliant or semi-compliant material, such aspolyethyleneterephthalate (PET), high density polyethylene, polyamides,polycarbonates, NYLON, polyurethanes, polyvinyl chloride, ethylene-vinylacetate copolymers, and mixtures and combinations thereof.

The stent 260 has a design similar to well-known expandable vascularstents that are employed to enlarge a restricted vein or artery. Suchvascular stents have a generally tubular design that initially iscollapsed to a relatively small diameter enabling them to pass freelythrough an artery or vein of a patient. The stent 260 is configured suchthat it eccentrically expands to a lateral side of the catheter body254. In particular, the inner surface of the stent 260 is suitablyaffixed to one side of the catheter body 254, whereas the inner surfaceof the stent 260 adjacent the opposite side of the catheter body 254 isfree. The balloon 258 is suitably bonded to the opposite side of thecatheter body 254, such that its expansion will expand the free side ofthe stent 260.

The proximal adapter 262 comprises a guidewire port 264, an electricalconnector 266, and an inflation port 268. As illustrated in FIG. 39, thecatheter 252 has a guidewire lumen 270, signal wire lumen 272, andinflation lumen 276 longitudinally extending through the catheter body254. The guidewire lumen 270 is capable of receiving a guidewire (notshown). The signal wire lumen 272 houses signals wires 274, whichdistally terminate at the electrodes 256 and proximally terminate in theelectrical connector 266 on the proximal adapter 262. Inflation mediummay be conveyed into the inflation port 268 on the proximal adapter 262,through the inflation lumen 276, and into the interior of the balloon258 in order to place the balloon 258 into its expanded state.

In alternative embodiments, a self-expanding stent similar to any one ofa variety of well-known self-expanding vascular stents, may be employed.In this case, a balloon is not required.

A method of delivering the catheter 252 into a selected cerebral bloodvessel 220 of the brain 200 will now be described with respect to FIGS.42A-42D. Like in the previous methods, a guidewire 34 is routed into acerebral blood vessel 220 distal to a selected stimulation site 222(FIG. 42A). The jugular vein or femoral vein, for examples, can be usedas the access point into the patient's vasculature. Once properplacement of the guidewire 34 is achieved, the catheter 252 is threadedover the proximal end of the guidewire 34, and the catheter 252, whilethe balloon 258 is in its deflated state, is distally advanced up theguidewire 34 until the distal end of the catheter 252 is adjacent theselected stimulation site 222 (FIG. 42B). Next, inflation medium isconveyed through into inflation port 268 of the proximal adapter 262,such that the balloon 258 is placed into its expanded state (FIG. 42C).As shown, the free side of the stent 260 has expanded against one sideof the vessel wall, thereby urging the distal end of the catheter 252,and more importantly, the electrodes 256, against the opposite side ofthe vessel wall. The guidewire 34 is then removed from the catheter 252,and thus, the patient's body, and the balloon 258 is deflated byremoving the inflation medium from the interior of the balloon 258 outof the inflation port 268 of the proximal adapter 262 (FIG. 42D). Asshown, the stent 260 remains expanded, such that the electrodes 256 arechronically urged against the vessel wall. Significantly, contraction ofthe balloon 258 allows the blood to flow through the stent 260. Theelectrical connector 266 on the proximal adapter 262, which extends fromthe patient's body (e.g., from the access point of the jugular vein orfemoral vein), is then connected to the implanted stimulation source 14(not shown).

Referring to FIG. 43, a delivery kit 280 that includes a stimulationlead 282 with an expandable electrode stent 284 will now be described.The body of the electrode stent 284 has a design similar to well-knownexpandable vascular stents that are employed to enlarge a restrictedvein or artery. The electrode stent 284 comprises a plurality ofelectrodes 286 that are suitably mounted, e.g., by soldering or welding,to the body of the stent 284. The stimulation lead 282 comprises asignal wire 288 that is similar in construction to the signal wire 16 ofthe previously described stimulation lead 12. The signal wire 288 iselectrically coupled to the electrodes 286 of the stent 284, such thatthe electrodes 286 can be operated in a monopolar mode. Alternatively,the multiple signal wires 288 can be coupled to the electrodes 286, suchthat the electrodes 286 can be operated in a bipolar mode.

The delivery kit 280 comprises a balloon catheter 290 that is configuredto deliver the stimulation lead 282 to a selected stimulation sitewithin a cerebral blood vessel using a balloon catheter 290. Thecatheter 290 comprises an elongate, flexible, catheter body 292, aninflatable balloon 294 mounted on the distal end of the catheter body292, and a proximal adapter 296 mounted on the proximal end of thecatheter body 292. The catheter body 292 can have the same dimensionsand be composed of the same material as the previously describedcatheter body 44. The proximal adapter 296 comprises a guidewire port298 and an inflation port 300. The balloon 294 is of similarconstruction as the previously described balloon 258, and iscircumferentially mounted to the distal end of the catheter 290, suchthat the balloon 294 will expand radially outward in all directions(shown in phantom in FIG. 43) when an inflation medium is introducedinto the balloon 294. The stent 284 can be placed around the deflatedballoon 294, such that expansion of the balloon 294 will radially expandthe stent 284 (shown in phantom in FIG. 43).

Referring to FIG. 44, the catheter 290 has a guidewire lumen 302 andinflation lumen 304 longitudinally extending through the catheter body292. The guidewire lumen 302 is capable of receiving a guidewire (notshown). Inflation medium may be conveyed into the inflation port 300,through the inflation lumen 304, and into the interior of the balloon294 in order to place the balloon 294 in its expanded state.

In alternative embodiments, a self-expanding stent similar to any one ofa variety of well-known self-expanding vascular stents, may be employed.In this case, a balloon is not required.

A method of delivering the stimulation lead 12 into a selected cerebralblood vessel 220 will now be described with respect to FIGS. 45A-45C.Once proper placement of the guidewire 34 is achieved (as shown in FIG.43A), the delivery catheter 290 is threaded over the proximal end of theguidewire 34, and the catheter 290, while the stent 284 is placed overthe deflated balloon 294, is distally advanced up the guidewire 34 untilthe distal end of the catheter 290 is adjacent the selected stimulationsite 222 (FIG. 45A). Next, inflation medium is conveyed into theinflation port 300 on the proximal adapter 296, such that the balloon294 (not shown) is placed into its expanded state (FIG. 45B). As shown,the stent 284 has radially expanded against the vessel wall, therebyurging the electrodes 286 against the vessel wall. The balloon 294 isdeflated by removing the inflation medium from inflation port 300 on theproximal adapter 296, and the catheter 290, with the guidewire 34, isremoved from the patient's body (FIG. 45C). As shown, the stent 284remains expanded, such that the electrodes 286 are chronically urgedagainst the vessel wall. If additional stimulation leads 12 are to beplaced in other selected stimulated sites, the steps performed in FIGS.45A-45C can be repeated. The proximal end of the stimulation lead (orleads), which extends from the patient's body (e.g., from the accesspoint of the jugular vein or femoral vein), is then connected to theimplanted stimulation source 14 (not shown).

Referring to FIGS. 46 and 47, a delivery kit 310 that includes astimulation lead 312 with a helical electrode structure 316 will now bedescribed. The stimulation lead 312 takes the form of a catheter, whichcomprises an elongate flexible catheter body 314, the helical electrodestructure 316 formed at the distal end of the catheter body 314, and anelectrical connector 318 mounted to the proximal end of the catheterbody 314. The catheter body 314 can have the same dimensions and becomposed of the same material as the previously described deliverycatheter 290.

The helical electrode structure 316 comprises a resilienthelically-shaped member 320 disposed through the distal end of thecatheter body 314. The resilient member 320 can be composed of anysuitable material that can be pre-shaped into a helical member, such asnitinol. The helically-shaped member 320 carries an array of electrodes322 that can be applied to the surface of the helically-shaped member320, e.g., by coating the helical electrode structure with anelectrically conductive material. As illustrated in FIG. 48, thecatheter 312 comprises a signal wire lumen 324 longitudinally extendingthrough the catheter body 314. The signal wire lumen 324 houses signalswires 326, which distally terminate at the electrodes 322 and proximallyterminate in the electrical connector 318.

The delivery kit 310 comprises a slideable guide sheath 328 that ismovable along the axis of the catheter body 314 (shown by arrows in FIG.46). Moving the sheath 328 in the distal direction over the helicalelectrode structure 316, collapses it into a compact, low profile linearform for introducing into a blood vessel (shown in phantom in FIG. 47).Moving the sheath 328 in the proximal direction away from the helicalelectrode structure 316, allows it to spring open into stable contactwithin the blood vessel (FIG. 46).

A method of delivering the catheter 312 into a selected cerebral bloodvessel 220 will now be described with respect to FIGS. 49A-49D. Onceproper placement of the guidewire 34 is achieved (as shown in FIG. 43A),the guide sheath 328 is distally advanced up the guidewire 34 until thedistal end of the guide sheath 328 is located proximal to the selectedstimulation site 222 (FIG. 49A). Next, the guidewire 34 is removed fromthe guide sheath 328, and the helical electrode structure 316 of thecatheter 312 is inserted into the proximal end of the guide sheath 328,such that the helical electrode structure 316 is placed into itscollapsed linear state (shown in phantom in FIG. 49B). The catheter 312is then introduced through the guide sheath 328 until the helicalelectrode structure 316 is deployed from the distal end of the guidesheath 328 into the blood vessel 320 adjacent the stimulation site 222(FIG. 49C). As illustrated, the helical electrode structure 316 assumesits three-dimensional expanded state, such that the electrodes 322 areplaced into stable contact with the blood vessel 320. The guide sheath328 is then removed from the patient's body, and the electricalconnector 318 of the catheter 312, which extends from the patient's body(e.g., from the access point of the jugular vein or femoral vein), isthen connected to the implanted stimulation source 14 (not shown).Depending on the configuration of the electrodes 322 and the connectionto the stimulation source 14, the brain tissue surrounding thestimulation site 222 of the blood vessel 220 can be electricallystimulated in a monopolar or bipolar mode.

The previously described embodiments and methods provided electricalstimulation of the brain tissue through a vessel wall (i.e., theelectrode(s) were in direct contact with the brain tissue, and thusstimulated the brain tissue through blood and vascular tissue. The braintissue can be directly stimulated, however, by introducing theelectrodes through a puncture site within the blood vessel, and thenplacing the electrodes into direct contact with the brain tissue.

For example, referring to FIG. 50, a brain stimulation delivery kit 330arranged in accordance with another preferred embodiment of the presentinvention will now be described. The kit 330 comprises the previouslydescribed stimulation lead 92 and associated pusher element 36, thepreviously described guidewire 34, a delivery catheter 332, and a stylet334. As previously described, the stimulation lead 92 comprises anelectrode 96 with a lumen 98 that allows the electrode 96 tolongitudinally slide along a shaft, and in this case, the stylet 334.

The stylet 334 comprises a laterally flexible, yet axially rigid, shaft336 and a sharpened distal tip 338 that is capable of penetratingtissue, and in particular, vascular tissue. Alternatively, other tissuepenetrating devices, such as lasers, can be used to penetrate throughvascular tissue. The delivery catheter 332 comprises an elongate,flexible, catheter body 340 and a guidewire lumen 342 (shown in FIG. 51)longitudinally extending through the catheter body 340. The guidewirelumen 342 is configured to singly receive the guidewire 34, stylet 334,and stimulation lead 92. The delivery catheter 332 further comprises aproximal adapter 344 suitably mounted on the proximal end of thecatheter body 340. The proximal adapter 344 comprises a guidewire port346 out which the guidewire 34 may extend when the delivery catheter 332is introduced over the guidewire 34. The guidewire port 346 also servesas a port through which the stimulation lead 92 can be introducedthrough the delivery catheter 332.

The catheter body 340 may be composed of the same material and have thesame dimensions as the previously described catheter body 44. Unlike thecatheter body 44, however, the distal end of the catheter body 340 isconfigured to be deflected at an obtuse or perpendicular angle relativeto the general axis of the catheter body 340. In the illustratedembodiment, the distal end of the catheter body 340 is deflected usingpull wire technology. In particular, the catheter 332 comprises apullwire lumen 348 that longitudinally extends through the catheter body340 (shown in FIG. 51), and the proximal adapter 340 further comprises apullwire port 352. The pullwire lumen 348 houses a pullwire 350, whichis suitably attached to the distal end of the catheter body 340, andproximally extends out from the pullwire port 352 on the proximaladapter 340. Thus, it can be appreciated that pulling the pullwire 350in the proximal direction will, in turn, laterally deflect the distalend of the catheter body 350, as shown in phantom in FIG. 50.

The distal end of the catheter body 340 can be deflected using othertechnologies. For example, the distal end of the catheter body 340 canbe composed of a super-elastic alloy, such as Nitinol, that deforms whenexposed to body temperature. In this case, the catheter 332 ispreferably delivered to the vessel using a guide sheath (not shown),such that the distal end of the catheter body 340 is not exposed to bodytemperature, and thus, maintains its straight geometry duringintroduction through the patient's vasculature.

Referring now to FIGS. 52A-52H, the kit 330 can be used to deliver thestimulation lead 92 into the sub-arachnoid space 228 of the patient'shead, thereby allowing the electrode 96 of the stimulation lead 92 to bemore freely placed anywhere along the cortex 202 of the brain 200.

First, the guidewire 34 is routed into a superficial blood vessel 227adjacent the sub-arachnoid space 228 (e.g., a superior cerebral veinbranching off of the superior sagittal sinus) until the distal end ofthe guidewire 34 is distal to a selected puncture site 230 (FIG. 52A).The jugular vein or femoral vein, for examples, can be used as theaccess point into the patient's vasculature. Once proper placement ofthe guidewire 34 is achieved, the delivery catheter 332 is threaded overthe proximal end of the guidewire 34, and distally advanced up theguidewire 34 until the distal end of the catheter 332 is adjacent theselected puncture site 230 (FIG. 52B). Next, the guidewire 34 is removedfrom the catheter 332 via the guidewire port 346 on the proximal adapter340 (not shown), and the pull wire 350 extending from the pullwire port352 on the proximal adapter 340 (not shown) is pulled in the proximaldirection in order to deflect the distal end of the catheter body 340towards the selected puncture site 230 (FIG. 52C). Alternatively, if thedistal end of the catheter body 340 is composed of a super-elasticalloy, the distal end of the catheter body 340 will automaticallydeflect upon exiting a guide sheath (not shown).

Next, the stylet 334 is introduced into the guidewire port 346 on theproximal adapter 340 (not shown) and through the catheter body 340 untilthe distal end of the stylet 334 deploys out from the distal end of thecatheter body 340 (FIG. 52D). As shown, the deflection of the distal endof the catheter body 340 has angled the sharpened distal tip 336 of thestylet 334 towards the wall of the vessel 230. Further advancement ofthe stylet 334 will then cause the distal tip 336 to puncture the vesselwall, thereby forming an exit point 234 into the surrounding braintissue. (FIG. 52E). The electrode 96 of the stimulation lead 92 is thenthreaded over the stylet 334, and, by pushing the pusher element 36,distally advanced up the stylet 334, through the exit point 234 in thevessel wall, and into contact with the surrounding brain tissue (FIG.52F). In this case, the stimulation lead 92 will be placed into thesub-arachnoid space 228 in contact with the exterior of the cortex 202.Manipulation of the pusher element 36 allows the electrode 96 to benavigated within the sub-arachnoid space 228, so that it can be placedin direct contact with a selected stimulation site 232 on the cortex 202(FIG. 52G). In some cases, it may be desirable to introduce astimulation lead through a lumen (not shown) within the stylet 334,rather than over the stylet 334. In this manner, any seal createdbetween the stylet 334 and the exit point 234 in the vessel wall can bemore easily maintained. Whichever way the stimulation lead is delivered,the stylet 334 can be provided with steering functionality (e.g., byhaving a torqueable or bendable distal tip), in which case, manipulationof the stylet 334 will aid in proper placement of the electrode 96. Oncethe electrode 96 is properly placed, the pusher element 36 can then beelectrolytically detached from the electrode 96 and removed from thedelivery catheter 332 (FIG. 52H).

If additional stimulation leads 12 are to be placed in other selectedstimulated sites, the steps performed in FIGS. 52F-52H can be repeated.The delivery catheter 332, along with the stylet 334, is then removedfrom the patient, and the proximal end of the stimulation lead (orleads), which extends from the patient's body (e.g., from the accesspoint of the jugular vein or femoral vein), is then connected to theimplanted stimulation source 14 (not shown).

It is believed that exiting the venous system, which has relatively lowblood pressures, rather than the arterial system, which has relativelyhigh blood pressures, may limit bleeding through the fenestrated vessel.If navigation through the arterial system is desired, however, themeningeal arteries may be used to provide an exit point, sinceintra-mennegies bleeds are considered much less risky than those thatwould otherwise be caused by creating exit points in other intra-cranialarteries, such as those branching off of the vertebral artery orinternal carotid artery. In whichever vessel the exit point is created,the distal end of the stimulation lead 92, which will ultimately be leftwithin the patient's body, may be coated with a thrombogenic material inorder to minimize the loss of blood through the exit point. Optionally,the blood flow through the fenestrated vessel can be minimized bytotally or partially occluding the flow of blood through the vesselusing a balloon apparatus. Of course, the extent to which thefenestrated vessel is occluded and time of the occlusion should becarefully monitored to minimize the risk of stroke. Notably, if ameningeal artery, which has a superfluous blood flow, is used, the riskof stroke will be further minimized.

Other types of the stimulation leads can be delivered into directcontact with brain tissue via fenestrated blood vessels. For example,FIG. 53 illustrates a brain stimulation delivery kit 360 arranged inaccordance with another preferred embodiment of the present invention.The kit 360 comprises a stimulation lead 362, which takes the form of acatheter, and the previously described guidewire 34 and stylet 334. Thecatheter 362 is similar to the previously described delivery catheter332, with the exception that the catheter 362 additionally compriseselectrical stimulation capability.

In particular, the catheter 362 comprises an elongate, flexible,catheter body 364, a plurality of ring electrodes 366, and a proximaladapter 368 mounted on the proximal end of the catheter body 364. Thecatheter body 364 can have the same dimensions and be composed of thesame material as the previously described catheter body 44. The proximaladapter 368 comprises the previously described guidewire port 346 andpullwire port 352, as well as an electrical connector 370.

In addition to the previously described guidewire lumen 342 and pullwirelumen 348 in which there are disposed a guidewire (not shown) and apullwire 350, respectively, the catheter 362 further comprises a signalwire lumen 372 longitudinally extending through the catheter body 364,as illustrated in FIG. 54. The signal wire lumen 372 houses a pluralityof signal wires 374 that distally terminate at the respective electrodes366 and proximally terminate in the electrical connector 370 on theproximal adapter 368.

Referring now to FIGS. 55A-55D, the kit 360 can be used to deliver thecatheter 362 into the sub-arachnoid space 228 of the patient's head,thereby allowing the electrodes 366 of the catheter 362 to be morefreely placed anywhere along the cortex 202 of the brain 200. Onceproper placement of the guidewire 34 is achieved (as shown in FIG. 53A),the catheter 332 is threaded over the proximal end of the guidewire 34,and distally advanced up the guidewire 34 until the distal end of thecatheter 332 is adjacent the selected puncture site 230 (FIG. 55A).Next, in the same manner described above in FIGS. 52C-52E, the distaltip 336 of the stylet 334 is deployed from the catheter 332 and into thesub-arachnoid space 228, creating an exit point 234 through the vesselwall (FIG. 55B). The distal end of the catheter 332 is then advancedover the stylet 334, through the exit point 234 in the vessel wall, andinto the sub-arachnoid space 228 in contact with the exterior of thecortex 202 (FIG. 55C). The distal end of the catheter 332 can then benavigated within the sub-arachnoid space 228, so that the electrodes 366can be placed in direct contact with a selected stimulation site 232 onthe cortex 202 (FIG. 55D). Alternatively, the catheter 332 or stylet 334can be provided with steering functionality, in which case, steering ofthe catheter 332 or stylet 334 will aid in proper placement of theelectrodes 366. Once the electrodes 366 have been properly placed, thestylet 334 is then removed from the patient's body. If steeringfunctionality is not provided to the catheter 332, the distal end of thecatheter 332 is preferably composed of a malleable material, such thatthe catheter 332 retains its shape, and thus, the electrodes 366 remainat their desired locations, when the stylet 334 is removed. Ifadditional catheters 362 are to be placed in other selected stimulatedsites, the steps performed in FIGS. 55A-55D can be repeated. Theproximal end of the catheter (or catheters), which extends from thepatient's body (e.g., from the access point of the jugular vein orfemoral vein), is then connected to the implanted stimulation source 14(not shown).

As with the distal end of the previously described stimulation lead 92,the distal end of the catheter body 364 is preferably coated with athrombogenic material in order to minimize the loss of blood through theexit point. Alternatively, the distal end of the catheter body 364 maybe provided with a radially expanding mechanism, such as a balloonand/or stent, or a radially expanding substance, such as hydrogel, suchthat the exit port will be sealed with the distal end of the catheterbody 364 upon expansion of the mechanism or substance. Or,alternatively, the catheter body 364 can be provided within an ablativeelement, such as an ablation electrode, the operation of which willcauterize the exit point. As previously described, the blood flowthrough the fenestrated vessel can be minimized by totally or partiallyoccluding the flow of blood through the vessel using a balloonapparatus.

Referring to FIG. 56, a brain stimulation delivery kit 380 arranged inaccordance with still another preferred embodiment of the presentinvention will now be described. The kit 380 comprises an arrayedstimulation lead 382, and the previously described guidewire 34,delivery catheter 332, and stylet 334.

The arrayed stimulation lead 382 comprises a laterally flexible, yetaxially rigid, shaft 384, a base member 386, an array structure 388formed of a plurality of flexible stimulation leads or splines 390connected to the base member 386, and an electrical connector 392mounted to the proximal end of the shaft 384. The splines 388 arepreferably made of a resilient inert material, like Nitinol metal orstainless steel. Thus, the array structure 388 can be alternately placedinto a compact, collapsed low-profile state in the presence of acompressive force, and a two-dimensional fanned state (shown in phantom)in the absence of a compressive force. In the illustrated embodiment,three splines 390 form the array structure 388. Additional or fewersplines 390, however, could be used to form the array structure 388.Each spline 390 carries an electrode 394 at its distal end. Of course,additional electrodes 392 can be used. The electrodes 394 can bearranged in a monopolar or a bipolar arrangement.

As illustrated in FIG. 57, the arrayed stimulation lead 382 furthercomprises a signal wire lumen 396 longitudinally extending through theshaft 384. The signal wire lumen 396 splits off into three separatelumens (not shown) that respectively extend through the splines 390. Thesignal wire lumen 396 houses signal wires 398, which are distallyconnected to the electrodes 394 (after passing through the respectivelumens within the splines 390) and proximally connected to theelectrical connector 392.

The guidewire lumen 342 of the catheter 332 (shown in FIG. 51) isconfigured to singly receive the guidewire 34, stylet 334, and arrayedstimulation lead 382. Because the arrayed stimulation lead 382 has alarger profile than the previously described stimulation lead 92, thediameter of the guidewire lumen 342 should be larger than that requiredto receive the stimulation lead 92. In this case, the stimulation lead382 is preferably deployed from a larger blood vessel, such as thesuperior or inferior sagittal sinuses.

Referring now to FIGS. 58A-58D, the kit 380 can be used to deliver thestimulation lead 382 into the sub-arachnoid space 228 of the patient'shead, thereby allowing the electrodes 392 of the stimulation lead 382 tobe more freely placed anywhere along the cortex 202 of the brain 200.

First, the blood vessel 227 is fenestrated in the same mannerillustrated in FIGS. 52A-52E to create an exit point 238 at a selectedpuncture site 236. The distal end of the catheter 332 is then advancedover the stylet 334, through the exit point 234 in the vessel wall, andinto the sub-arachnoid space 228 in contact with the exterior of thecortex 202 (FIG. 58A). The stylet 334 is then removed from the catheter332, and the arrayed stimulation lead 382 is inserted into the guidewireport 346 (not shown), such that the array structure 388 (shown inphantom) of the catheter 332 is placed into its collapsed state (FIG.58B). The array structure 388 is then introduced through the catheter332 until the array structure 388 deploys out from the distal end of thecatheter body 340 into the sub-arachnoid space 228 (FIG. 58C). Asillustrated, the array structure 388 assumes its two-dimensional fannedstate, thereby spreading the electrodes 392 across the surface of thecortex 202. The delivery catheter 332 is then removed from the patient,and the proximal end of the stimulation lead, which extends from thepatient's body (e.g., from the access point of the jugular vein orfemoral vein), is then connected to the implanted stimulation source 14(not shown).

Although particular embodiments of the present invention have been shownand described, it should be understood that the above discussion is notintended to limit the present invention to these embodiments. It will beobvious to those skilled in the art that various changes andmodifications may be made without departing from the spirit and scope ofthe present invention. Thus, the present invention is intended to coveralternatives, modifications, and equivalents that may fall within thespirit and scope of the present invention as defined by the claims.

1. A method of treating a neurological disorder in a patient,comprising: delivering a stimulation lead within a cerebral bloodvessel; intralumenally puncturing a wall of the blood vessel to createan exit point; and introducing the stimulation lead through the exitpoint into contact with brain tissue the stimulation of which treats theneurological disorder.
 2. The method of claim 1, further comprisingstimulating the brain tissue with the stimulation lead to treat theneurological disorder.
 3. The method of claim 1, wherein theneurological disorder is a degenerative disorder.
 4. The method of claim1, wherein the neurological disorder is a brain infarction.
 5. Themethod of claim 1, wherein the brain tissue is cortical brain tissue. 6.The method of claim 1, wherein the brain tissue is deep brain tissue. 7.The method of claim 1, wherein the stimulation lead is advanced within asub-arachnoid space of the patient's head upon exiting the blood vessel.8. The method of claim 1, further comprising electrically connecting thestimulation lead to a stimulation source.
 9. The method of claim 8,further comprising implanting the stimulation source within the patient.10. The method of claim 8, wherein the stimulation lead is connected tothe stimulation source in a monopolar mode.
 11. The method of claim 8,wherein the stimulation lead is connected to the stimulation source in amultipolar mode.
 12. The method of claim 1, wherein the stimulation leadis an electrical stimulation lead.
 13. The method of claim 1, whereinthe stimulation lead comprises an exposed signal wire and an electrodecoupled to the exposed wire.
 14. The method of claim 1, wherein thestimulation lead comprises a catheter having a catheter body, a signalwire extending through the catheter body, and an electrode mounted tothe catheter body in electrical contact with the signal wire.
 15. Themethod of claim 1, wherein the vessel wall is intralumenally puncturedby introducing a guide element through the vessel wall, and thestimulation lead is introduced through the exit port by introducing thestimulation lead along the guide element.
 16. The method of claim 15,wherein the guide element is a stylet.
 17. The method of claim 15,wherein the guide element is steerable.
 18. The method of claim 15,wherein a distal end of the stimulation lead is malleable.
 19. Themethod of claim 15, further comprising: introducing a catheter having adistal end into the blood vessel; and deflecting the distal end of thecatheter towards the vessel wall at an obtuse or perpendicular angle;wherein the guide element is introduced from the deflected distal end ofthe catheter through the vessel wall.
 20. The method of claim 19,wherein the catheter comprises the stimulation lead.
 21. The method ofclaim 1, further comprising occluding the flow of blood through theblood vessel upstream from the exit point.
 22. The method of claim 1,further comprising sealing the exit port after the stimulation lead hasbeen introduced through the exit point.
 23. The method of claim 1,wherein the stimulation lead is an arrayed stimulation lead.
 24. Amethod of treating a disorder in a patient, comprising: delivering astimulation lead within a blood vessel; intralumenally puncturing a wallof the blood vessel to create an exit point; introducing the stimulationlead through the exit point into contact with tissue the stimulation ofwhich treats the disorder.
 25. The method of claim 24, wherein thedisorder is a degenerative disorder.
 26. The method of claim 24, whereinthe disorder is an infarction.
 27. The method of claim 24, furthercomprising stimulating the tissue with the stimulation lead to treat thedisorder.
 28. The method of claim 24, further comprising electricallyconnecting the stimulation lead to a stimulation source.
 29. The methodof claim 28, further comprising implanting the stimulation source withinthe patient.
 30. The method of claim 28, wherein the stimulation lead isconnected to the stimulation source in a monopolar mode.
 31. The methodof claim 28, wherein the stimulation lead is connected to thestimulation source in a multipolar mode.
 32. The method of claim 24,wherein the stimulation lead is an electrical stimulation lead.
 33. Themethod of claim 24, wherein the stimulation lead comprises an exposedsignal wire and an electrode coupled to the exposed wire.
 34. The methodof claim 24, wherein the stimulation lead comprises a catheter having acatheter body, a signal wire extending through the catheter body, and anelectrode mounted to the catheter body in electrical contact with thesignal wire.
 35. The method of claim 24, wherein the vessel wall isintralumenally punctured by introducing a guide element through thevessel wall, and the stimulation lead is introduced through the exitport by introducing the stimulation lead along the guide element. 36.The method of claim 35, wherein the guide element is a stylet.
 37. Themethod of claim 35, wherein the guide element is steerable.
 38. Themethod of claim 35, wherein a distal end of the stimulation lead ismalleable.
 39. The method of claim 35, further comprising: introducing acatheter having a distal end into the blood vessel; and deflecting thedistal end of the catheter towards the vessel wall at an obtuse orperpendicular angle; wherein the guide element is introduced from thedeflected distal end of the catheter through the vessel wall.
 40. Themethod of claim 39, wherein the catheter comprises the stimulation lead.41. The method of claim 24, further comprising occluding the flow ofblood through the blood vessel upstream from the exit point.
 42. Themethod of claim 24, further comprising sealing the exit port after thestimulation lead has been introduced through the exit point.
 43. Themethod of claim 24, wherein the stimulation lead is an arrayedstimulation lead.